Peterson Engineering Corporation copyright 2004
Two sample pages from Buck's 14" Gears installation instructions
Note: Instructions undergo continual revision and upgrade, and the instructions used in this example (Buck's 14" Gears pages 2 & 3) are not necessarily current.
3. Unscrew the declination locking knob, turning it counterclockwise. Remove the knob assembly (includes knob, escutcheon plate and 2 spacers – one on each side of the escutcheon plate).
4. Put a finger or two through the hole in the now exposed plastic drive cover, and push against the steel plate inside. This is the outer clutch plate. It’s riding on 2 short pins and we don’t want it to fall off and onto the declination drive motor below. Now, using the 3/32” hex wrench, remove the 6 socket head cap screws holding the plastic drive cover in place. Note that the 2 bottom screws are a bit longer than the others.
5. You are now going to perform a brief test demonstrating a drive weakness that you will be correcting. Reinstall the declination knob along with the escutcheon plate and spacers. Gripping the scope’s rear handle pull the scope’s tube to a horizontal position and tighten the declination locking knob. As you release your grip on the handle watch the front of the scope’s tube to see if it moves. You may find that your tube moves noticeably – possibly more than 1/4 inch! Again grip the scope’s rear handle, and loosen the dec locking knob. With the scope held level, tighten the locking knob once more, but this time closely examine the engagement of the worm to the worm gear (see arrow in photo). As you loosen your grip on the scope’s rear handle and the drive takes up the load of the imbalanced tube, notice that the worm may be pushing away from the worm gear and/or the two right hand parts of the drive (which magnify any motion) are scissoring together slightly, compressing the worm engagement spring. You may not see worm movement if scope is well balanced, and you may have to unbalance it slightly (perhaps by putting the corrector cover on) to see the problem we are attempting to demonstrate. This scope is relatively massive. When it slews the scope’s inertia loads up the worm similar to the imbalance demonstration you have just run. This worm movement will be corrected as you proceed with your Gear Kit installation
6. Now that the engagement spring test is complete, remove the declination knob along with the escutcheon plate and spacers and set them aside.
7. Place a few paper towels or some newspaper on your work surface, as you’ll be dealing with greasy parts. Remove the steel clutch plate (see photo). The clutch plate should lift right out but it may be stuck to the aluminum worm gear due to the suction of the grease. If it is, there are 3 alternatives. The first is to just place a kitchen knife between the outside edge of the steel plate and the side of the aluminum gear and gently pry it off, being careful not to mark either plate or gear. The second is to work a piece of dental floss between the outer clutch plate and the gear. The third (and easiest method) is to leave it in place for the moment and remove it with the aluminum worm gear (as described in the next 2 steps). The plate is covered with grease. Place it on the newspaper or paper towel. You have now exposed the 5-¾ inch (146mm) diameter aluminum worm gear.
8. You will now remove the aluminum worm gear. With the finger of one hand, lift the bottom right section of the drive as shown in photo. This will back the worm gear away from the drive gear. Now, with the free hand, remove the worm gear and place it on the newspaper/paper towel alongside of the outside steel clutch plate. If you have difficult time removing the gear try wiggling it while turning the drive knob. If it still does not want to come off use the hex wrench like a hook. Stick the short end of the wrench behind the gear and gently pull out the gear at different spots around its edge to keep the gear from cocking - it will come right off.
9. Disconnect the wiring from the drive assembly by unplugging the 3 small connectors from the right hand side of the printed circuit board (see photo). Do not disturb the largest connector on the left side of the circuit board. Slightly lift each top connector locking tab with a thumbnail and pull the connector off of the circuit board socket with the other hand. CAUTION. During this step and all subsequent steps in the gear installation procedure, be extremely careful not to pull on any of these small delicate wires. They will break or pull off readily and if this happens you may end up buying replacement parts from Meade.
Return to Buck's 14" Gears webpage